Why does the CDC recommend wearing a mask indoors, even if you are fully vaccinated?

San Francisco, 29 July 2021:

What science supports masking after vaccination?

The mask helps prevent the spread of the coronavirus. They are the literal layer between you and the virus in the air and help prevent infection.

Public health authorities are demanding more masks because there is clear and increasing evidence that fully vaccinated people can develop a breakthrough COVID-19 infection. .. This is especially true for new mutant strains of concern. Fortunately, a COVID-19 infection is far less likely to lead to serious illness or death in vaccinated people.

Some conditions increase the likelihood of breakthrough infections in vaccinated individuals: more viruses circulate in the community, lower vaccination rates, and more contagious mutants.

If vaccinated people can become infected with the coronavirus, they can also spread it. Therefore, the CDC’s recommendation that vaccinated people remain masked in indoor public spaces to help stop the virus infection.

Where do the guidelines apply?

The CDC mask recommendations are for regions in the United States that have more than 50 new infections per 100,000 inhabitants or have tested positive for more than 8% the previous week. According to the CDC’s own definition, “substantial” community infections are 50-99 cases per 100,000 people per week, with “high” being over 100.

For example, Los Angeles County far exceeded that mark in mid-July, with more than 10,000 cases of coronavirus per week.

Using these criteria, CDC guidance was applied to 63% of US counties on the day of publication.

Who is actually protected by masking recommendations?

Encouraging fully vaccinated people to continue wearing masks is primarily aimed at protecting unvaccinated children. This includes children under the age of 12 who are not yet eligible for vaccination in the United States. The CDC also recommends public masking for vaccinated people who have unvaccinated household members, regardless of community infection rates.

Unvaccinated people are significantly at increased risk of becoming infected with SARS-CoV-2 and developing complications from COVID-19.

How do new varieties like Delta change things?

Preliminary data suggest that an increase in mutants such as Delta may increase the likelihood of breakthrough infection in people who received only the first vaccination. For example, one study found that a single dose of Pfizer vaccine was 51% for older alpha mutants and only 34% for delta mutants in terms of preventing symptomatological illness. Was only effective.

The data are more reassuring for fully vaccinated people. Even after two doses, the Pfizer vaccine provides strong protection against delta mutants, according to actual data from Scotland and various other countries. In preliminary studies in Canada and the United Kingdom, researchers noted that their effectiveness against symptomatic diseases was only “slightly” reduced from 93% of alpha mutants to 88% of deltas.

However, other recent preliminary reports from highly vaccinated countries such as Israel and Singapore are calm. From January to April 2021, before the spread of the Delta variant, Israel reported that the Pfizer vaccine was 97% effective in preventing symptomatic disease.

Preliminary data reported by the Israeli Ministry of Health in late July show that the Pfizer vaccine is only 41% effective in preventing symptomatic disease due to the more widespread distribution of delta variants since June 20, 2021. was. According to an analysis using Singapore government data, 75% of recent COVID-19 infections were found in at least partially vaccinated people, but most were not severe. ..

However, in all reports and studies, the vaccine remains very good at hospitalization with delta mutants and prevention of serious illness-probably the result we care most about.

All of this new data supports WHO’s global recommendation to continue wearing masks even for fully vaccinated individuals. Most of the world still has low vaccination rates and uses vaccines of various effects, and each country has a different burden of circulating SARS-CoV-2 virus.

It makes sense for the CDC to change masking recommendations more conservatively, as public health officials believe the number of cases and breakthrough infections in the United States are pointing in the wrong direction. ..

What conditions in the United States (again) justify masking?

It makes sense that the CDC did not immediately change its recommendations to be consistent with WHO’s June guidelines. The situation for COVID-19 in the United States is very different from most parts of the world due to the overall high nationwide vaccination rate and the overall low burden of hospitalization and death for COVID-19.

In addition, some experts were worried that the official message that vaccinated people should wear masks might discourage unvaccinated individuals from looking for a vaccine.

However, as President Joe Biden said on July 27, “new research and concerns about delta variants” is behind the CDC’s change in masking recommendations.

In some areas, community infections are increasing even among vaccinated people. A new preliminary study that has not yet been peer-reviewed suggests that delta mutants are associated with 1000-fold higher viral load in patients than found in older strains. Also, early reports show that vaccinated people infected with the delta mutant can carry as much virus as unvaccinated people, which can spread to others. there is.

Changing the recommendations does not mean that the old one was wrong, but that the conditions have changed. What is the conclusion? Masks help reduce coronavirus infections, but vaccines still provide the best protection. ET Health World